Die for forming undercut castings



July 11, 1950 L. H. MORIN 2,514,893

DIE FOR FORMING UNDERCUT CASTINGS Filed July 1, 1944 L 1 I Wm l, I11 .6. 4A

INVENTOR 4011/6 MGR/N ATTORNE Patented July 11, 1950 UNITED STATES PATENT OFFICEWI Louis H. Morin, Bronx, N. Y.

Application July 1, 1944-, Serial No. 543,171

10 Claims.

particularly, the invention relates to dies of the class described wherein undercut recesses are formed in at least one surface of the resulting casting without the use of cores and in a twopart die structure, particularly wherein the dies are mounted for swinging or arcuate movement,

invention are disclosed, and in which the separate parts are designated by suitable reference characters in each of the views; and in which:

Fig. 1 is a diagrammatic view showing three coupled scoops of separablefastener stringers in "cross section, indicating one type of scoop structure made with my form of dies which I employ. i

- Fig; 2 is a view similarto Fig. 1, showing another form of scoop structure produced from different dies than those employed in producing the scoops of Fig. l. i

Fig. 3 is a sectional View on the line 3 3 of Fig. 2, showing only the surface section of the scoops, as seen in Fig. 2, simply to indicate the longitudinal contour of scoops made with the dies employed.

Fig. 4 is a diagrammatic sectional view showin a pair of dies mounted to swing about a common axis in forming scoops of the type and kind illustrated in Fig. 1, and omitting the tape on which the scoop is-formed.

Fig. 5 is a view similar to Fig. 4, showing dies in an open position.

Fig. 6 is a partial section on the line 6 6 of Fig; 4, and also illustrating the stringertape upon whichthescoop is cast.

Fig. 7 is a view similar to 'Fig. 4, showing dies pivotedupon spaced axes for producing scoops of thetype and kind illustrated in Fig. 2, and also omitting the tape on which the scoop is formed.

Fig. 8-is a view similar to Fig. '7, showingthe dies in an open position; and

Fig. 9 is a section on the lines-9 of Fig. '7,

v and showing the scoop. cast on a stringer tape.

Inthe accompanying drawing, the dies illustrated have cavities for forming scoops of separable. fastener stringers, and particularly what I term corelessscoops. That is to say, scoops which are die cast directly upon the stringer tapes-.bythe usev ofapairof swinging dies'without utilizing core pins or other core members for forming the undercut or recessed portions, of the scoops in producing the female coupling of the scoops, preventing transverse separation of coupled scoops.

In the construction of dies prior to recent developments by me, it has been impossible to form undercuts'in die cast, molded or otherwise formed products without the use of multiple dies or cores movable relatively to the dies. In more recent developments by me, I have conceiveddies hay;- ing cavities which will form undercuts in the resulting products by either moving the dies angularly to each other in ejecting the product from the dies, or by so forming the undercut surfaces and other surfaces of the diesyas to facilitate automatic ejection of the casting and movement of the casting relative, to dies which are separated in a common plane in the manner of conventional die movement. 1

The present application deals with the production of dies which will swing in an arcuate path or about one or more axes in separation of the dies and in freeing the casting or product from the cavity orimpressions of the dies in order to form undercut recesses or channels in predetermined surfaces of the resulting products.

The method of forming castings with such dies is described and claimed in a copending application Serial Number 543,170, filed July 1, 1944 now abandoned.

In Figs. 4, 5 and 6 of the drawing I have shown a pair of dies to and H having interfitting bearing portions as at [2, to swing about a common axis in the form of a shaft or rod [3. ,Bothdies l0 and ,l l have registering cavitiesj lil and IS on adjacent surfaces thereof which in the construction shown, are the same crossjsectional form as well as longitudinal sectional form. .In cross sectional form, the combined cavities 14 will form at the upper surface of the resulting casting IS a longitudinal recess 11, the radius of which is common with the axis l3; In other words, the walls l8 and IQ of the cavities I4 and I5 have a curvature concentric with the swinging movement of the die parts I0 and II on the axis l3. Opposed walls 20 andv 2iof the cavities l4 and I5 are also curved and are preferably of a radius common to or slightly less than the radius of the walls i8 and I9, so that the convex sunface 22 of the casting is free to fit and operate in the concave surface I! of an adjacent casting, as will appear from a consideration of Fig.1 of the drawing.

.In other Words, the convex surfacespzzioi coupled scoops seat and operate in the concave surfaces ll of adjacent scoops, and the slight difference in curvatures provides a free bending of the stringer tapes one upon the other, the structure being more or less of a modified ball and socket coupling between the scoops. This engagement of the scoops also retains coupled scoops against transverse separation, as will clearly appear from a consideration of Fig. 1 of the drawing.

The scoops 56 are held against lateral separation by more or less diamond shaped heads" 23, the upper and lower projections 24 of which will engage upper and lower recesses of adjacent scoops, as will clearly appear from the longitudinal section of the scoop, as seen in Fig. 6 of the drawing. It will here be kept in mind that the irregular longitudinal contour ofv the" scoop, as seen in Fig. 6, is carried out to both sides of the scoop-in transverse parallellines, so that there is no wall structure on the scoop int'erf'e'r ing with the swinging separation of the dies" HT and H in ejecting the casting. The section in Fig; 6 of the drawing is taken through the head portion 23 of the scoop,.as seen in Fig. 6', whereas in Fig. 1', a section through the recessed portion 25' thereof is seen in the middle scoop of said figure. By employing a sli htly 1ess radius on the surfaces 22 of the scoops, it will be a pa ent that these convex surfaces converge to a degree with the concave surfaces [1, thus providing a free separation of the dies one from the other.

In Fig". 6 of the drawing I have shown at 2 6 the gate opening on the partingline of the dies through which casting material is injected into the cavities from anozzle part of which is diagrammatically shown at 21. In this figure is also indicated at 28" a part of a stringer tape upon which the casting is formed, and at 29 is indicated' one of a pair of grippers employed to engage the tape to support the tape and castingin the se aration of thedies and also to feed a formed casting into a, lowered position, as indicated in dotted lines at 30 in Fig. 4, in order to form the next successive casting on the stringer tape 23. This operation is continued indefinitely until the required number of castings are formed in defining each stringer length.

In Figs. 7, 8 and 9 of the drawing I have shown at 3i and 32 a pair of similar dies mounted for swinging movement upon independexit and spaced axes 33 and 34. The dies 3i and 32 have cavities 35 and 36 adapted to collectivjely form, cast scoops .31 of the type and kind illustrated Fig. 2' of the drawing. These astings are of the same longitudinal section as the castings Ni, as will appear from a consideration of Fig. 9'. In other words, they will include outer heads 38 similar to the heads 23, inwardly of which are the opposed recesses. 39'.

v Fig; 9, 40 represents the gate o ening Slinilar to the gate 26, 4| part of the injection iioz'zle, similar to the nozzle 21, and '42 the stringer tape upon which the casting 37 is formed. Grippers are also employed, and one of these grippers is indicated at 43.

The cast scoops 31 differ from the scoops i6 providing sharp ridges 44' on the convex surfaces of the scoops and corresponding recesses 45 on the opposed or undercut surfaces of the scoops, This result is produced by providing walls 46 and 41 in the cavities 35 and 36 which are concentric to the swinging movement of the dies 3| and 32' on their pivots, the walls intersecting on the parting line of the dies to form the ridges 44 in each casting. The cavities 35 and 36 have opposed curved surfaces 48 and 49 preferably of a radius greater than the radius of the surfaces 46 and 4'! and also intersecting on the parting line of the dies to form the longitudinal groove, recess or channel 45 in each casting. It may be noted that the radius of curvature of surfaces 48 and 49 of dies 3! and 32, respectively, is less than the distance to such surfaces from the pivot centers 33 and 34, about which each die 3! and 32 moves.

It. will be understood that the walls 43 and 49 could be parallel to the walls 46 and 4? but by contracting these walls, the corresponding surfaces on the castings formed will converge to the sides thereof and produce between coupled scoops of two stringers spaces as at 50, note Figs. 2 and 3, which will provide free bending or flexing movement of coupled stringers. The clearances as at 50 are materially greater than. the slight clearance shown in Fig. 1, and. this is due to the fact'that the ball and. socket structure in itself, as shown in Fig. 1, provides for free flex-- ing or bending movement of the stringers.

Thewalls of the die cavities above defined, in other words, the walls 46 and 41-, produce the curved converging walls 5! and 52 on the resulting scoops, whereas the walls 48 and 49 produce the walls 53 and 54 of the scoops. These walls carry the longitudinal irregular cross section shown in' Fig. 9 throughout the fullwidth of the scoops.

It will be apparent that dies of the general type and kind herein disclosed may have: cavities of any shape or form to produce products of anykind: consistent with: the formation of undercut recessed portions on at least one surface of the resulting products. Further, the illustration in the accompanying drawing of the methods of controlling movement of the dies is only illustrative of two adaptations of the invention. Any means may be employed to guide the dies in a curved or arcuate path, or parallel to at least one surface of the die' and the resulting product and capable of freeing an opposed surface by reason of the relative contour or curvature of such opposing surface. It is also desirable, for free ejection of a, casting, tohave these opposing surfaces of the die cavity and the resulting product converging in the direction of the side surface of the product, or inother words, converging with respect to the depth of the cavity. Another way of explaining this structural feature would be to say that the product formed between two dies would have: its greatest thickness at the parting. line of the dies.

In referring to the formation of die castings, it will be understood that any types and kinds of materials may be employed in the sense of metallic or plastic materials, and in molding or forming processesof any type or kind; wherein it is practical to form products in die cavities of impressions by movement of the dies toward and from each other in curved paths, and particularly in separation of the dies by such movement to eject the castings or molded products from the die cavities. In the accompanying drawings, the castings are shown as formed on a mounting, such for example, as the stringer tape; In many instances, no mountings will be employed.

Having fully desji'ibed my invention, what I content throughout the length of the cavity and opening through adjacent surfaces: of the dies, the walls of each die cavity being? of irregular contour longitudinally thereof, the walls of "the cavity defining the irregular contour being parallel in: .each cavity, and said dies being mounted for separating movementon a common axis with which that wall of the cavity forming the concave contour of the c'asting is concentric. '2. A die for shaping a predeterminedproduct having an undercut recess on one surface defined by curved walls, said die comprising two die parts, each die part having an impression, the impressions of the die parts registering on the parting line of the dies, each impression having undercut surfaces extending beyond the limits of the registering portions of said impressions at the parting line to form in the product shaped by said die impression the undercut recess in one surface of said product, said dies being movable in curved paths to free the dies from the undercut surface of the product in the separation of said dies, and the movement. of said dies being on independent and spaced axes.

3. A pair of coreless dies for forming die cast separable fastener scoops; said dies having registering cavities and mating faces and each die having a cavity opening in suchface bounded by parallel edge portions merging successively into converging, diverging and again converging edge portions; each cavity opening lying entirely within the confines of the mating face; each cavity presenting transverse sections, at right angles to the plane of the cavity opening, all bounded by an inner wall spaced from and substantially parallel to the die face and upper and lower similar arcuate walls; said cavities together defining a complete die cast scoop when the cavity openings are in registry; and each of said dies being mounted for separating movement about a fixed pivot center located above said upper arcuate walls, the radius of curvature of said upper arcuate wall of each die being equal to the distance to such wall from the pivot center about which each such wall moves, and the radius of curvature of said. lower arcuate wall of each die being less than the distance to such wall from the pivot center about which each such wall moves.

4. A pair of coreless dies for forming die cast separable fastener scoops, said dies having registering cavities and mating faces and each die having a cavity opening lying entirely within theconfines of the mating face; said cavities together defining a complete die cast scoop when the cavity openings are in registry; each cavity being bounded by upper and lower arcuate walls; each die having a channel opening through one end thereof and extending inwardly to the die cavity, each said channels together forming a gate passage when the dies are in registering position; and each of said dies being mounted for separating movement about a fixed pivot center located above said upper arcuate walls, the radius of curvature of said upper arcuate wall of each die being no greater than the distance from the pivot center of such die to any point on said upper "arcuate wall "and the" radius (if-curvature of'said' lower arcuatewau of each die being no greater than the distance from the pivot center of such die to any'point on said lowerarcuatewall. V

5i A'pairof dies for forming die cast separable fastener scoops, saiddies having cavities and mating faces'and each "die "having a; cavity opening in such face bounded by parallel edge portions merging"successively; into converging, di-

verging and again converging edge portions, each cavity presenting transverse sections, at right "angles to the plane of the cavity opening, all bounde'clby' an 'inn'erwall spaced from and substantially parallel 'to' 'theidie face'and upper and lower similar arcuatewall's; and s'aiddies being mounted for separanng msvement' about two, spaced, fixed, pivot centers located above said upper arcuate walls.

6. A pair of dies for forming die cast separable fastener scoops, said dies having cavities and mating faces and each die having a cavity opening in such face bounded by parallel edge portions merging successively into converging, diverging and again converging edge portions, each cavity presenting transverse sections, at right angles to the plane of the cavity opening, all bounded by an inner wall spaced from and substantially parallel to the die face and upper and lower similar arcuate walls, and said dies being mounted for separating movement about two, spaced, fixed, pivot centers located above said upper arcuate walls, the center of curvature of each upper arcuate wall substantially coinciding with the pivot center of such wall.

7. A pair of dies for forming die'cast separable fastener scoops, said dies having cavities and mating faces and each die having a cavity opening in such face bounded by parallel edge portions merging successively into converging, diverging and again converging edge portions, each cavity presenting transverse sections, at right angles to the plane of the cavity opening, all bounded by an inner wall spaced from and substantially parallel to the die face and upper and lower similar arcuate walls, and said dies being mounted for separating movement about two, spaced, fixed, pivot centers located above said upper arcuate walls, the radius of curvature of said arcuate walls of each die being no greater than the distance from each pivot center to any point on either of the arcuate walls which move about such center.

8. A coreless die for forming die castings having an undercut recess on one surface thereof, said die comprising two die parts having adjacent abutting surfaces, said die parts each having registering cavities which have openings in said abutting surfaces and which are defined by walls extending into each die part inwardly of said surfaces, said cavity openings lying entirely within the confines of said abutting surfaces, said walls of the cavities of the die parts which define the undercut recess in the casting converging and intersecting at said abutting surfaces, and said die parts being mounted to swing on spaced independent axes.

9. A coreless die for forming die castings having an undercut recess on one surface thereof, said die comprising two die parts having adjacent abutting surfaces, said die parts each having registering cavities which have openings in said abutting surfaces and which are defined by walls extending into each die part inwardly of said surfaces, said cavity openings lying entirely. within the confines of said abutting surfaces,'each of said die parts being mounted for separating movement about a fixed axis, said walls of the cavities of the die parts which define the undercut recess in the casting converging and intersecting at said abutting surfaces, and other opposed walls defining the die cavities bein concentric with respect to the axis of each die part.

10. A diecomprising a pair of die parts having registering cavities in adjacent sides of said parts, each of said cavities having curved walls defining concave and convex surfaces on op posite sides of each said cavities, said concave and convex surfaces converging in the direction of the depth of their respective cavities, said die parts being mounted on independent axes and movable relatively to each other in a die 8 rectlon which parallel the curvature of one of their said curved walls.

LOUIS H. MORIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,593,614 Zeiler July 27, 1926 2,198,634 Richter Apr. 30, 1940 2,207,600 'Seareer July 9, 1940 2,322,908 Porex June 29, 1943 2,338,735 Person Jan. 11, 1944 FOREIGN PATENTS Number Country Date 517,876 Great Britain 1- Feb. 12, 1940 

